WebGIS Based HTML5 Study

WebGIS is the product of the combination of network technology and GIS technology.it promotethe application and popularization of GIS.The development of network technology also contributed tothe development of WebGIS. In order to achieve a strong ability to interact with the WebGIS,thedevelopers generally have to use Flex, Silverlight, and abandon HTML technology. With the release ofthe HTML5standard,it bring a new opportunity of WebGIS development. HTML5plug a lot of theAPI to improve the interactive capabilities of the Webpage, the abilities of the HTML5is even betterthan Flex and other technology. The main content and achievement of this paper are showed asfollows:Firstly,the thesis described the HTML5featues in detail. Based on the HTML5features, theServer-client mixed tectonic model was selected as the HTML5WebGIS tectonic model. Then theOGC Web Geographic Information Services was studied profoundly, especially by using FilterEncoding to filter output of spatial data.Secondly, This paper compares and analyzes the WebSocket technology and Ajax technology.And summed up Their respective advantages used in WebGIS. HTML5support local storage bydifferent techniques. combining with this feature this article simply built a the spatial vector data cacheto accelerate the capture and display of vector data.Thirdly,the canvas API was encapsulated to different object-oriented feature classes, which wasconvenient to draw and manage the map,as well as reduce the difficulty of using the CanvasAPI.Because the graphics drawn in canvas does not exist in the DOM of web page,the achievement ofsimulation of the2level DOM event is to support the response and interaction of features.In addition,using server method and client method to achieve buffer analysis, and make a simple comparison.Finally, combining with the result of the research above, the author developed a HTML5-basedon Web GIS system, which adopted Apache as a Web server, GeoServer as a spatial server isdeveloped in PHP and JavaScript language.The implement of based-HTML5Web GIS validated that the HTML5technology can be used inthe GIS, discovered the deficiencies of the system through the operation of the system and outlook forthe future research work.